Blood Brothers
by trenchcoatsexual
Summary: "Looking at it through Castiel's eyes, Sam could see what the allure was. He could see how the bond between him and Dean was so attractive, so beautiful to Castiel. He could see why Castiel would get off on it." Wincestiel PWP, companion to Eternal.


**Rating: **NC-17  
**Pairing: **Sam/Cas/Dean  
**Words: **2k  
**Warnings: **Light bondage, light voyeurism, light dirty talk, incest kink  
**A/N: **Same 'verse as Eternal. I was writing my mini bang but this wouldn't leave me alone. I'm obviously sexually frustrated. Also, this contains explicit Wincest, which Eternal did not, so if that squicks you out, don't read.

* * *

It was probably something psychological, and wasn't it just like Sam to get all hard about analyzing an angel's psyche? But it made sense, you didn't need a degree in Psychology to see it. Hell, you didn't even need that one course of Psychology Sam had taken back at Stanford and passed with straight As. All you needed was a little background on Castiel and a range of emotion longer than your arm.

Dean at least had the former, but Sam wasn't so sure about the latter.

The point is, Sam knew where the fascination stemmed from, knew why it was there, and it would have been pretty sad in theory if it weren't so goddamn hot in practice.

It traced back to the same thing everything else they did traced back; the reason they acted the way they did, the reason they'd been through all they had, the reason that they were together, essentially.

Family issues.

Castiel used to have maybe a few thousand brothers and sisters. Now they were all pretty much gone, dead for some reason or other. Castiel was alone, with none of the siblings he'd had for centuries, since the beginning of time. Sam had no idea how lonely that must be.

More so when you get to comparing the relationship Castiel had with his siblings with the relationship he sees every day between Sam and Dean.

The two practically live in each other's pockets, spending every second of every day at each other's sides. Sometimes they get pretty sick of each other and end up bickering about something stupid, but the love they feel for each other is evident in every look, every smile, every touch. Sam and Dean can't get enough of each other, whether it be sexual or out of simple companionship.

Castiel and his siblings were soldiers, warriors. They didn't have much opportunity to form any kind of emotional bonds with each other. Hell, they didn't have any emotions to bond _with._

Looking at it through Castiel's eyes, Sam could see what the allure was. He could see how the bond between him and Dean was so attractive, so beautiful to Castiel. He could see why Castiel would get off on it.

Ever since the first time Sam and Dean had realized Castiel's little 'kink'- Castiel's breath getting faster, little moans spilling out of him every time Dean called Sam 'little brother' or 'baby boy' and coming quicker than ever before- they sometimes took a whole night to just exploit it and have Castiel wriggling and desperate, turned on beyond belief.

The ropes around Castiel's wrists and the headboard were more of a reminder than a restraint, because all three of them knew that Castiel could tear them off with a simple thought. But he didn't, staying cooperatively in place, with his arms over his head, content to just watch. The strip of fabric in his mouth wasn't there for any kinky purposes either- although both Sam and Dean had to admit that the sight was absolutely sinful. It was simply so Castiel would remember to keep quiet and listen and watch, because the show was _for him _after all. It wouldn't do to have him interrupting it.

There are moments where Sam forgets that he's just part of a show right now and that Castiel is the audience, that Castiel shouldn't be participating just yet. But Castiel is _so _close, and so pretty, and it's hard to refrain from leaning down and trailing his lips over those high cheekbones, along that long expanse of throat.

Then Dean is snapping his hips in harder as if he knows that Sam is getting distracted, and all temptations fly out of Sam's mind immediately.

"So pretty, little brother," Dean is drawling at the bend of Sam's neck and shoulder, eyes fixed on Castiel under Sam.

Sam's eyes are squeezed shut, overwhelmed by the feeling of his brother filling him up so well. He leans his head to the side slightly, exposing his neck some more, inviting Dean to take it, which Dean does willingly. He starts sucking and trailing his teeth down, leaving little marks, laving his tongue over them.

"_Dean,_" Sam whispers. "Please. _More._"

Dean knocks his forehead against the side of Sam's head fondly, noses along the shell of his ear and says loud enough for Castiel to hear. "Anything for my little guy."

Both Castiel and Sam moan loudly, probably irrevocably stoking Dean's ego, and Dean leans up and starts fucking in harder, making Sam jerk forwards each time.

Dean fucks harshly into him, making Sam cry out, face just inches over Castiel's but it doesn't affect him right now, too distracted by the feeling of getting his prostate hit every few thrusts. He spreads his knees a little bit farther on the mattress from their position on either side of Castiel's, making his body lower slightly, barely brushing against the angel's.

While Sam is too distracted by Dean's thrusts to really focus on Castiel, Castiel isn't that lucky. He has no choice but to stare admiringly up at the two beautiful brothers above him, the younger one with his face twisted up in pleasure as the older one thrusts into him frantically, plush lower lip caught between his teeth.

Castiel's knuckles were white from gripping the rope so tightly, blunt fingernails digging into his palms so hard they drew blood. His body was taut, tight with the effort to keep still and not thrust up, rut his aching dick against the nook where Sam's thigh transitioned into hip. Sam had the loveliest hipbones, sharp and protruding, begging to be ground up against. But Castiel pressed his own hips down onto the mattress, reminded himself that he was merely an observer for now and waited for them to decide to include him.

Sam's arms were about to give out and he wanted to get down on his elbows, but that would bring his face right over Castiel's and it wasn't time for him to be brought in yet, so he flexed his fingers on the mattress beside the angel's shoulders.

Castiel watched with rapt eyes as Dean started slowing down and Sam made a protesting noise in the back of his throat.

"Shh, Sammy," Dean muttered, although Castiel could see by the set of his brow that holding back was difficult for him too. He ran a hand along Sam's side, up and down, and then went up to curl lightly in Sam's long hair, turning his head to the side. Dean pressed little kisses down the side of Sam's face, from his temple, down his cheek and to the corner of his mouth.

"Isn't he pretty, Cas?" Dean whispered against Sam's skin, just loud enough for the angel to hear him.

Castiel couldn't help but squirm, excited at finally being able to participate, even if it was just answering a question. He nodded twice, blue eyes fixed on Sam's sweaty face. Sam's hazel eyes smiled down at him, tongue snaking out to wet his lips.

"Yeah, he is," Dean continued, nuzzling Sam's neck fondly and Sam made a little whining sound, happy at the attention. "My little brother, so big and strong and so fucking beautiful." There was an underlying feral growl to Dean's tender words and it made a little bead of precome leak out of Sam.

"My perfect little brother," Dean murmured reverently, eyes closed as he inhaled the scent of sweat accumulated on Sam's throat. "All mine to take care of and make feel _so good._ Do I make you feel good, baby boy?"

Sam moaned, head falling forward, hair falling in his face. "Fuck yes, big brother," he ground out, noticing how Castiel's eyes squeezed shut momentarily before fixing on him, wide and glistening, and how his hips shifted, hitched slightly. "So good, Dean."

There was a light pressure on Sam's back and Sam went with Dean's push, sinking down lower and lower until his chest was almost flush to Castiel's. The hand still in Sam's hair pulled slightly, moving his head aside so Dean could lean over the angel's face over Sam's shoulder.

"He's your little brother now too, Cas," Dean whispered softly and Castiel's eyes widened. "He's yours and mine now…you gonna help me take care of him?"

Sam's arms trembled and not because of the pressure they were under.

Castiel nodded again, earnestly, and Dean smiled. He reached up with his free hand to wind behind Castiel's head and undo the gag, then up to the ropes at his wrists to undo the knot.

Once Castiel was freed, he wasted no time before claiming Sam's face between both of his hands and pulling him down for a needy kiss, tongue slipping in between the younger Winchester's lips. Dean, content to let them make out, straightened up and shifted his hips, finding the perfect angle to start fucking into Sam again, making his brother cry out into the angel's mouth.

"Cas," Sam gasped when their mouths fell apart. "Cas, please." He buried his face into the angel's neck and Castiel cradled his head there, fingers running through the soft, sweaty hair.

"Of course, Sam," he murmured, kissing the spot behind Sam's ear.

Castiel shifted under them, snaking his legs out from under Sam and hooking them over Sam's thighs. They both groaned harshly when their dicks knocked together.

Using one hand and bracing his weight on the strong angel's chest, Sam reached down and aligned his cock, grateful that they had had the presence of mind to prep both himself and Cas during the foreplay so they wouldn't have to wait for it now.

Dean slowed down so that Sam could have some stability as he slipped inside, Castiel's opening widening as his pushed in. Sam sucked on the edge of the angel's jaw, both of them moaning as Sam got the head in, Castiel's rim sealing around it. Dean licked his lips, kissing along Sam's shoulders and back.

Sam kept pushing in, slowly, teasingly, and Castiel growled impatiently. He dug his heels into the meat of Dean's ass, pushing him forward so he thrust fully into Sam, who in turn bottomed out inside Cas, making the three of them cry out at the same time.

"Sweet fuck, Cas," Dean groaned.

"_Move,_" Castiel demanded, voice laced with authority, and Dean was powerless to resist. He straightened, adjusted again and started fucking into Sam with a newly found vigor.

Dean and Castiel found a rhythm, Castiel shifting up when Dean pulled back, then shifting down when Dean thrust in so Sam was pushed inside. It was maddening and too much for Sam, who couldn't move or react and just held along for the ride, gripping Castiel's hips tight enough to bruise.

Dean's lips met Castiel's over Sam's shoulder and Sam buried his face in Castiel's neck to give them room.

"He's ours, Cas," Dean murmured against the angel's lips. "Yours and mine."

Castiel's hands tightened, one on the back of Sam's neck, the other one on Dean's biceps. Sam's lips were on his neck and Dean's breath was on his cheek and his dick was caught in one of those delicious hipbones he had been marveling earlier. His eyes locked with Dean's, who smiled at him before turning to bury his face in Sam's hair, obviously close to the edge.

Sam turned his face and pressed it against the side of Castiel's, who clenched his inner muscles around him as he thrust up, making the man whine. His fingers tangled in Sam's hair and his other hand trailed down Dean's arm. He was lost; lost in the feeling of being with them both having them both, Dean trusting him enough to share the most precious part of himself- his Sammy, his little brother.

The brothers had never appreciated straightforward 'I love you's but Castiel thought that the kiss he planted on Sam's cheek as Sam writhed and convulsed, crying out as he came inside the angel, was just enough to get the point across.


End file.
